Double-thread sewing-machine



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0.' P. LITTLBAJOHN. l DOUBLE THREAD SBWINGlMAGHINE.

No. 421,590. Patented Feb. 18,-1890- K j 3 A il mullmllw WITNESSES:INVENTD @Mcm [uvam 5 Sheets-Sheet 2..

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C. F. LITTLEJOHN. DOUBLE THREAD SEWING MACHINE.v

No. 421,590. Patented Feb. 18, 1890.

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C. F. LITTL'BJHN.'

DOUBLE THREAD SEWING MAHINB. No. 421,590. Patented Feb. 18,v 1890.

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UNITED STATES Prrrmvrk OFFICE.

CHARLES F. LITTLEJOHN, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR OF ONE-HALFTO E. B. IVELCH, OF CAMBRIDGE, MASSACHUSETTS.

DOUBLE-TH READ SEWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 421,590, dated February18, 1890. Application iled November 19, 1885. Renewed December 2, 1887.Serial No. 256,794. (No model.)

To all whom it may concern:

Be it known that I, CHARLES F. LITTLE- JOHN, of Bridgeport, in thecounty'of Fairfield and State of Connecticut, have invented certain newand useful Improvements in DoubleThread Sewing-Machines, of which thefollowing is a specification.

The object of this invention is to furnish an improved double-threadsewing-machine of a simple andldurable character.

My improvements relate, iirst, to a horizontally-oscillating curved hookprovided with a peripheral groove and eyes to hold and carry the underthread through a loop of the upper thread on the needle, and with acent-ral cam,

which is formed to spread and hold a loop or bight of the lower threadin position to receive the descending needle, and to release or throwoff said loop after the needle has entered it.

My improvements also relate to certain combinations of devices and minorimprovements, all of which I will now proceed to describe and claim.

Of the accompanying drawings, forming a part of this specification,Figure 1 represents a front elevation of a sewing-machine provided withmy improvements. Fig. 2 represents an end elevation of the same, theWorkplatebeingshown in section. Fig. 3 represents a section on line fr,Fig. 2. Fig. 4 represents a section on line y y, Fig. 3,1ookingdownwardly. Fig. 5 represents a section on line e e, Figs. 1 and 3, andside elevation of the thread-hook. Figs. (i and 7 represent sideelevations of the thread-hook in different positions. Fig. 8 representsa top view of the thread-hook. Figs. 9 to 13, inclusive, representperspective viewsof the thread hook and needle, showing different stagesin the formation of the stitch. Fig.14 representsa bottom view of a partof the work-plate, showing the thread-hook in dotted lines. Fig. 15represents a section on line a," cc', Fig. 14. Fig. 16 represents asection on line y y', Fig. 14.

The same letters of reference indicate the same parts in all thefigures.

In the drawings, A represents the table, to which the base B of themachine is secured.

From this base the goose-neck or arm C rises in the usual manner.

and actuated by an eccentric on the main shaft F and by a pitman G,connected at its upper end with the short arm of said lever. Hrepresents the thread-hook, which is at tached to a substantiallyvertical stem or arbor H2, and is composed of a curved portion 2, Fig.8, about concentric with the axial center of said arbor, and a radialarm 3, connecting the portion 2 with said arbor, theupper side of thehook being substantially horizontal, so that it moves in a plane aboutat right angles with the line of movement of the needle N. The peripheryof the hook hasfa groove 6, for the reception of theunder thread, andtwo or more (preferably three) eyes '7, forming continuations of saidgroove to retain the thread in the groove, one of said eyes being at theheel, another near the point, and the third at about the middle of theperiphery of the hook. The orifice of the thread-eye at the point of thehook may be on the same curve as the remaining portion of the groove 6,for a purpose hereinafter described. The stem or arbor H2 of the hookis'journaled in a bearing-block R, attached to the frame or base of themachine, and is grooved to form gear-teeth 8, meshing with similar teeth9on a horizontal rod J, which is reciprocated longitudinally (but is notcapable of rotating) in the block R, and by its reciprocating movementsoscillates the arbor H2 and the hook thereon.

The rod J is reciprocated in this instance by means of an arm orextension Dr on the needle-lever, and a connecting-rod L, pivoted tosaid arm and to an ear K, aflixed to the rod J by means of a screw K',said screw serving to clamp the ear K upon the rod J. By loos`l eningthe set-screw K the rod J may be turned to present any portion of itstoothed surface to the shank of the thread-hook; hence as the rodbecomes worn it may be adjusted to bring unworn portions into opera'tive position. Atthe center of the hook or upon the end of the stem orarbor is the cam or hub I-I, which has a concave side 4 and a convexside 5, said concave side during a por- D represents the needle-lever,pivoted at E` IOO tion of the oscillating movement of the hookce-operating with the point of the hook in spreading and holding open aloop of the under thread, so that the descending needle may pass throughsaid loop, while the convex side is so formed that during another partof the oscillating movement of the hook it will come in cont-act withsaid loop and release or throw it off, so that it may be taken up by thesubsequent movement of the hook. Prior to the descent of the needle thehook stands in the position shown in Fig. 9, the under thread extendingfrom the seam on the work to the point of the hooi; in close proximityto the concave side of the hub or cam. Vhile the needle is descendingthe hook rotates backward, as indicated by the curved arrow in Fig. l0,and thus causes the portion of the under thread between the seam and thepoint of the hook to bear against the concave side of the hub or cam andbends said portion partly around the cam in the form of a loop Z, Figs.l0 and 1l, which is prevented from slipping upwardly off from the cam bythe concave side Li. The needle descends while the loop Z is thus heldand passes through said loop. A After the needle has entered the loop Z,and while it is completing its downward movement, the hook continues itsbackward rotation until the convex side of its hub is brought againstthe loop Z. The form of the convex side is such that it cannot retainsaid loop, but releases or casts it off, the loop then embracing theneedle and the upper thread thereon, and being tightened by thecompletion of the backward movement of the hook. After the loop Z isreleased and tightened the hook rotates forward, its point advancingtoward the depressed needle. J ust before the point of the hook reachesthe needle the latter begins to rise, and in so doing throws out fromone of its sides a loop Zf of the upper thread, said loop being enteredby the point of the advancing hook, as shown in Fig. l2, and thusretained on the hook while the needle is rising and the hook iscompleting its forward movement, as shown in Fig. 13. The needle inrising leaves the released loop Z of the lower thread around the loop Zof the upper thread, which is held upon the hook. The hook then rotatesbackwardiy out of the upper thread loop, leaving the latter interloopedby the lower thread, which is drawn through said loop by the point ofthe retreating hook. The operation is thus continued, each descent ofthe needle being through a loopof the lower thread first held and thenreleased by the hub of cam H', and each upward movement of the needlebeing followed by the entrance of the threadhook into the loop of theupper thread thus thrown out from the side of the needle, said hookretaining the upper thread-loop while the needle rises, and then movingbackwardly to draw the lower thread through and thus permanently holdsaid loop, the result being that the lower thread is iirst carriedaround each loop of the upper thread and then looped through it. Thiscontinued interlooping of the needle and looperthreads forms thewell-known Grover it' Baker, or double chain-stitch, seam. As soon asthe point of the hook withdraws from the upper thread-loop Z said loopis drawn or tightened by a take-up consisting of two eyes 1? lt',affixed to the 'frame of the machine at opposite sides of the needle-barand another eye Q on the needle-bar, the eye Q being placed at a pointwhich in the course of the stroke of the needle-barmoves equally aboveand below the iixed eyes l R', so that the slack of the upper thread istaken up both by the upward and downward stroke of the needle bar.

I have in some cases found it advantageous to form a downward in elineon the underside of the thread-hook from the point to or partly to theheel, as best shown in Figs. 5, (5, and 7. This incline causes the hookin passing through the loop Z of the upper thread to pull said threaddownwardly, and thus tighten or set the preceding stitch. l have also insome cases employed a spring-plate a, attached at one end to the heel ofthe hook and extending along the underside thereof nearly to the point,its opposite end being free. Said plate stands parallel with and so nearto the under side of the hook that it bears upon the loop of the upperthread and prevents said `loop from moving independently or beingdisplaced during the backward movement of the hook. Said loop isloosened by the backward movement of the hook, owing to the inclineabove described, which draws down or elongates the loop during theforward movement of the hook, and therefore loosens it during thebackward movement. lf the loosened loop were free to move laterally onthe hook, it would be liable to get in the path of the descending needleand receive the latter. The spring-plate prevents this by retardin g theloop or preventing its free movement toward the needle until the pointof the needle has descended below the lower end of the loop. Thethread-eye 7 at the point of the hook is shown as extending along theperiphery of the hook in line with the groove 6. The eye thus disposedcauses the under thread to stand off from the side of the needle, asshown in Fig. 12, when the loop Z is thrown out from the needle and thehook is moving forward to enter said loop. The un der thread is thusprevented from pressing `against the loop Z so that the latter is freeto stand out from the needle and receive the hook.

c represents a projection on the underside of the throat-plate CZ of themachine, said projection extending nearly down to the plane of the upperside of the thread-hook and containing the hole c, through which theneedle passes. Said hole is formed with a straight and flat side or walllO, which affords a support for the loop Z of the upper thread,

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thrown off from the needle by the upward movement of the latter, asabove described, and prevents said loop from yielding when the point ofthe advancing hook reaches it, thus insuring the prompt entrance of thehook into said loop. The needle-hole is also provided with a recess l2at one side of the wall, said recess receiving the thread of the upper'loop when said loop is being taken up.

g represents a socketed cylindrical holder, Fig. 5, journaled in theblock R, so as to be capable of rotating therein, and provided with asocket eccentric to its periphery, in which socket the arbor H2 of thethread-hook is journaled. It will be seen that vby reason of theeccentricity of said arbor to the periphery of the holder a rotarymovement of the holder in the block R will move the arbor laterally withrelation to the spirallygeared rod I, so that any lost motion betweenthe spiral gears of the arbor and rod resulting from wear or other causecan be taken up by a rotary movement of the holder. A set-l screw tsecures the holder in a position to which it may be retained.

These improvements add materially to the effectiveness and smoothness ofthe operation of the machine. I do not limit myself to the conjoint useof all the speciedimprovements in one machine.` The hook may have itsunder side parallel with its upper side instead of inclined,if desired,and the loop-retardiug spring may be omitted.

The thread-hook may be oscillated by any other suitable mechanism.'

I claim- 1. In a double-thread sewing-machine, an oscillatingthread-hook having a curved and peripherally-grooved arm and aprojection within the curve of said arm, concave on one side forretaining the thread and spreading the same for the entrance of theneedle, and convex on the opposite side for casting the thread off toengage with' the upper thread, whereby during a movement of the hook thethread is iirst held and then released by said projection, and means foroscillating said hook, substantially as described.

2. The oscillating hook provided with the curved portion grooved on itsouter face and perforated at its heel and point for the permanentengagement of the thread, and the cam or projection at the centerextending above the head of the hook for spreading and releasing thelower thread, combined with means for oscillating said hook, as setforth.

3. In a sewinganachine, the vertically-reciprocating needle N, carryingthe upper thread, in combination with the oscillating hook having theprojection Il thereon, with the concave and convex sides, and theperiph` eral groove with the retaining loops or eyes, and the eye at theend of the hook, whereby the hook is adapted permanently to carry thelower thread, spread the lsame for the reception of the upper threadedneedle, and then release said loop to enable the same to be contractedaroundthe upper thread, substantially as set forth.

4. The combination of the thread-hook having its shank or shaft groovedto form teeth, the rod J, grooved to form teeth intermeshing with thoseof the thread-hook, fixed bearings in which said rod is adapted to berecip- ,rocated to oscillate the thread-hook, a recipthread-hook movedby the arm K, and thel link I., uniting said arm and the lever D allarranged and operating substantially as described.

6. The combination, with the oscillating thread-hook having its shank orshaft spirally grooved, forming spiral teeth, of the reciprocating, rodJ, spirally grooved, forming teeth intermeshing with those on thethreadhook, whereby the bearing-point between the two may be changed,and bearings for preventing the rotation of said rod J, as set forth.

7. In a double-thread sewing-machine, a vertical shaft, ahorizontally-arranged threadlooper thereon, a curved hook portiontherefor, extending' in a horizontal plane and having an incline, andaloop-retardingspring on the under side of the curved hook, asdescribed, in combination with means for oscillating said looper,substantially as set forth.

8. In a double-thread sewing-machine, an oscillating thread-hook havinga peripheral groove and an eye, the longitudinal axis of which is inline with said groove at or near its point to guide the lower thread andcause the same to stand away from the needle, combined with means foroscillating said hook, as set forth. Y

9. In a double-thread sewing-machine, a vertical shaft, ahorizontally-arranged threadlooper mounted thereon, a curved hookportion therefor externally grooved, as described,

and having a thread-eye at its point, the longitudinal axis of said eyebeing in line with said groove, so as to present a continuation of thelatter, in combination with means for oscillating nsaid looper,substantially as set forth.

lO. In a double-thread sewing-machine, the combination of the needle,the thread-hook oscillating in aplane, substantially at right angleswith the line of movement of the needle and perforated at its point andheel to permanently retain the thread, and the throatplate having adownward projection containing the needle-hole, said hole having a' wallwhich terminates near the upper side of the hook and supports the upperthread-loopv while the hook is entering it, as set forth.

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11. The oombnation,with aneedle and the Intestimony whereof l havesigned my 1o means for reciprocating it, of the toothed name to Jnhisspecification, in the presence of thread-hook arbor H2, the holder inwhich two subscribing` Witnesses, this 12th da1 of Nosaid arbor isjournaled, Said holder being ecvember, 1885. centric 13o the arbor, thexed supporting- VV 1 w Y block in which the holder is capable of rota-CHARLES I" LH l LEJOU'N' ing, and the toothed rod J, j ournaled in saidW'itnesses: block and engaged with the arbor H2, and de- CHAS. SHULZ,vices for reciprocating said rod J, as son forth. A XVALTER NICHOLS.

